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Pediatr Radiol (2007) 37:310312 DOI 10.1007/s00247-006-0371-3
CASE REPORT
Diagnosis of aortic coarctation by tardus-parvus renal artery Doppler signal in an infant with multicystic dysplastic kidney: a case report
Kate Park & Kieran McHugh & William vant Hoff
Received: 24 July 2006 / Revised: 30 October 2006 / Accepted: 8 November 2006 / Published online: 9 January 2007 # Springer-Verlag 2007
Abstract We report an infant with known unilateral multicystic dysplastic kidney (MCDK) who underwent renal ultrasonography and Doppler spectral waveform analysis for investigation of hypertension. A tardus-parvus waveform was demonstrated in the renal artery on the normal side suggesting either renal artery or more proximal stenosis. Coarctation of the aorta was subsequently demonstrated.
Keywords Aorta . Coarctation . Multicystic dysplastic kidney . Hypertension . Doppler ultrasonography . Tardus-parvus waveform
Introduction
Hypertension is known to occur in unilateral multicystic dysplastic kidney (MCDK) but is rare, particularly in patients in whom the contralateral kidney is normal [13]. In such patients, other causes of hypertension must, therefore, be excluded with thorough assessment of both kidneys and renal arteries and, if no cause for the
hypertension is found, evaluation of the entire cardiovascular system.
The tardus-parvus waveform seen on Doppler ultrasonography of the renal arteries is an indication of a more proximal stenosis, most commonly renal artery stenosis. We report an infant with known unilateral MCDK and hypertension in whom Doppler ultrasonography of the renal artery on the contralateral side demonstrated a tardusparvus waveform subsequently shown to be due to an aortic coarctation. The case demonstrates the importance of investigation of the entire cardiovascular system in patients with unexplained hypertension, so that treatable causes, such as coarctation, are not missed.
Case report
An asymptomatic 5-month-old boy was reviewed in the nephrology clinic on account of a MCDK. Antenatal ultrasonography at 17 weeks gestation had shown left-sided hydronephrosis. At 6 weeks of postnatal age, following an uncomplicated birth at term, renal ultrasonography and a 99mTc-MAG3 study demonstrated a small, cystic, nonfunctioning left kidney typical of an involuting MCDK. The right kidney was sonographically normal, measured 6.2 cm in length (in a child...